Hair Growth Overview
Human hair grows in a cycle with three distinct phases: anagen (growth), catagen (transition), and telogen (resting). Each strand follows its own timeline, preventing simultaneous shedding.
Anagen Phase Duration
The anagen phase lasts 2-7 years. This growth phase determines hair length. Genetic factors play a role, explaining why some people can't grow hair beyond a certain length.
Hair Growth Rate
On average, hair grows about 1 cm per month. However, factors like age, genetics, hormones, and nutrition can significantly affect individual growth rates.
Scalp Hair vs. Body Hair
Scalp hairs have a longer anagen phase compared to body hairs. That's why scalp hair can grow longer. Body hair has a short growth phase, which explains its relatively shorter length.
Effects of Diet on Hair
Nutrient deficiencies, particularly biotin, iron, protein, and vitamins, can slow hair growth and lead to hair loss. A balanced diet supports healthy hair follicles and growth.
Hair Growth and Sleep
Lack of sleep can extend the telogen phase, reducing hair growth and increasing shedding. Sleep is crucial for various growth hormones that contribute to hair health.
Seasonal Growth Variation
Hair grows faster in summer due to improved blood circulation and higher levels of growth-promoting hormones, which are influenced by seasonal changes.